Final answer:
To calculate the equilibrium constant (Keq) for a reaction at 25°C, you need the equilibrium concentrations of products and reactants. Substitute these into the equilibrium expression Keq = [products]^coefficients / [reactants]^coefficients.
Step-by-step explanation:
You are asked to calculate the equilibrium constant (Keq) for a reaction at 25°C. To find Keq, you would typically use the formula Keq = [products]^coefficients / [reactants]^coefficients once the equilibrium concentrations are known. If you have the equilibrium concentrations of the products and reactants for a particular reaction at equilibrium, you can directly calculate Keq by substituting these values into the equilibrium expression.
For instance, if we have a reaction where the equilibrium concentration of HI is 0.156 M, H2 is 0.022 M, and I2 is also 0.022 M, and the reaction has a form of H2 + I2 → 2HI, Keq would be calculated as follows:
Keq = [HI]² / ([H2] × [I2]) = (0.156)² / (0.022 × 0.022)
The value of Keq is dimensionless and depends on the temperature. At 25°C, constants like the ion-product constant for water (Kw) are also available to help you calculate missing equilibrium concentrations.